two guys take a girl each, then all four of them enter a room, each guy takes a girl from behind on opposite sides of the room (like a tennis court), they proceed to ram the girl hard enough for them to moan, they ram their girls back and forth in an opposite fashion, this simulates two females playing tennis (in tennis, when a female hits the ball, she lets out a distinguishable moan)
"Tommy, me and you were totally playing tennis with those two girls last night. We blew them out of the water."
A euthamism for sexual acts.
"Where are Chris and Will?"
"They're 'playing tennis' at the moment"
the act of making out and/or messing around with a lesbian in a tennis court.
"Hey Courtney! Lets go play some tennis!"
"Man, i really wanna play some tennis right now. ;]"
"I was playing tennis with Sarah last night, and i think i'll play some more tonight."